Prepare v2020.04-rc4

Signed-off-by: Tom Rini <trini@konsulko.com>

Makefile

diff --git a/Makefile b/Makefile
index fa687f1..7fae3c2 100644
--- a/Makefile
+++ b/Makefile
@@ -3,7 +3,7 @@
 VERSION = 2020
 PATCHLEVEL = 04
 SUBLEVEL =
-EXTRAVERSION = -rc3
+EXTRAVERSION = -rc4
 NAME =
 
 # *DOCUMENTATION*